Corneoscleral biomechanical properties may influence the characteristics of short-term IOP elevations, and thus play an important role in an individual's susceptibility to glaucoma. Our hypotheses are: (a) eyes with certain corneoscleral biomechanical properties (i.e., low stiffness) are more capable of damping IOP (i.e., smaller, slower, and/or shorter elevations), and (b) these corneoscleral biomechanical properties are affected by aging processes resulting in reduced capability to dampen IOP. The specific aims are: Aim 1: To test the prediction that corneoscleral biomechanical properties affect short-term, dynamic IOP variations. We will examine in enucleated canine globes the influence of the natural variance or experimentally altered corneoscleral properties on the parameters of IOP elevations. Aim 2: To test the prediction that age-associated differences in corneoscleral biomechanical properties are correlated with the eye's ability to dampen IOP. We will examine whether there are age-related differences in physiologic, short- term IOP dynamics in human eyes. We will then investigate whether the age-associated differences in IOP parameters can be explained by the age-associated differences in the corneoscleral biomechanical properties. A novel ultrasonic technique will be used to non-invasively measure corneal properties in the human eye, establishing feasibility for future in vivo assessment and monitoring of corneoscleral properties. Significance: The proposed studies will detail the influences of the biomechanical characteristics of the corneoscleral shell on short-term IOP elevations, which will lead to the discovery of new measurable and modifiable glaucoma susceptibility factors that will improve clinical management of glaucoma. PUBLIC HEALTH RELEVANCE: Elevated intraocular pressure (IOP) is a primary risk factor for glaucoma. This study will investigate how corneoscleral biomechanical properties influence the characteristics of short-term IOP elevations, leading to the identification of new measurable indices for glaucoma susceptibility.